Ecology Ch 4-6
Ecology Study of the interactions between living things and their environment The interdependence of organisms can be organized into levels and changes in one level can have impacts on other levels
Levels of Organization in Ecology 1. Biosphere thin volume of Earth and its atmosphere that supports life 2. Ecosystem all living and nonliving parts of a particular place
3. Community all interacting organisms living in a area 4. Population all members of a species living in one place at one time 5. Organism one living thing in a population
Ecosystem/Organism
Within an ecosystem, the two types of environmental factors are: Biotic = living Ex) bacteria, protists, fungi, plants, and animals Abiotic = nonliving Ex) rocks/soil, air, sun, water
Habitat = place where organism lives Niche = organism s role in the environment Species can live in the same habitat but not share the same niche due to competition for resources
Organism s Response to Changing Environments: Tolerance curve graph of performance versus an environmental variable Ex) If a fish s water gets too hot or too cold, then they will slow down then eventually die Acclimation adjustment to an abiotic factor Ex) increase in red blood cells when you go up in altitude Migration moving to another more favorable habitat
Nutrient Cycles Why is it important to recycle nutrients such as C, O, N, P, and water? Matter (elements and compounds) must be put back into the ground (recycled) in order for organisms to be able to use them again Necessary for life to continue
Water Cycle Circulates freshwater between the earth s surface and the atmosphere. The water cools to form clouds (condensation) and water vapor which then creates precipitation (rain, snow, sleet, hail) Runoff moves water from the mountains to the rivers, lakes, streams, and groundwater The sun provides heat to start evaporation of water molecules from Earth s surface Plants also release water into the atmosphere by the process of transpiration
Carbon Cycle The cycling of carbon between carbon dioxide and organic molecules Plants take in carbon dioxide through photosynthesis Carbon also passes to other organisms through the food chain or web It the returns to the atmosphere and the Earth through respiration, waste or decomposition after death Coal and other fossil fuels can form from decomposing organic matter and burning it off, which called combustion
Nitrogen Cycle The conversion of nitrogen gas into other nitrogen forms so that plants and animals may use it Nitrogen fixation converts nitrogen gas into another form of nitrogen (ammonia) by bacteria in the soil and plant roots and by blue green algae in the ocean Waste and death/decomposition also release ammonia into the ground Ammonia then changes into another nitrogen form that plants can now use (nitrate and nitrite) with the help of more bacteria
Lightening and the addition of fertilizer are the final ways usable nitrogen gets into the soil The nitrogen passes to animals through the food chain The bacteria then convert nitrate and nitrite into nitrogen gas again (denitrification) and is released back into the atmosphere
Phosphorous Cycle Cycling of phosphorous from rocks to the food chain Phosphorous is introduced into the soil and water through the breakdown of rocks (weathering) Plants and fungus absorb the phosphorous from the soil The phosphorous then moves through the food chain to animals It then returns to the soil as waste or decomposed material
Energy Flow Food chain = linear feeding relationship from one trophic level to the next Trophic level = organism s position in the food chain or web Food web = feeding relationship with several interconnected food chains
Energy Flow 4 parts: producers, primary consumers, secondary consumers, tertiary consumers Sun is the ultimate source of energy Only 10% of the energy from one trophic level gets passed to the level above Reason: some energy is lost as heat, organisms need energy to live, and not all organisms get eaten
Community
Community Remember: Species can share a habitat, but not a niche because of competition for resources One species will win out and the other will be forced to find another resource or they will die off (natural selection)
Natural selection = organisms with traits better suited for an environment will survive and reproduce while other organisms die off Passing the beneficial trait to offspring creates an adaptation Variation in traits occurs from: DNA mutations, independent assortment, and random fertilization
Succession Other factors that contribute to changes in communities include succession Succession = series of changes in the composition of an ecological community over time Two types: Primary and Secondary
Primary Succession Building up of a community where life DID NOT previously exist Ex) bare rock (Stone Mountain, volcanic eruptions, glacial retreat), sand dunes
Secondary Succession Building up of a community where life DID previously exist Ex) natural disaster, forest fire
Pioneer Species First species to grow in an area Ex) lichen (fungus + algae), moss
Climax Community Stable, mature community that undergoes little or no change in species When equilibrium is reached after succession occurs
Species Interactions (Symbiosis) 1) Predation - act of one organism killing another for food Ex) snake hunting a mouse 2) Competition fighting for resources Ex) 2 lions fighting for a zebra 3) Parasitism one organism is harmed and the other benefits Ex) ticks, mosquitos
Species Interactions (Symbiosis) 4) Commensalism one organism benefits and the other is neither harmed or helped Ex) fish swimming under a shark to eat the scraps 5) Mutualism both organisms benefit Ex) Bees and flowers
Population
Population Population Growth Rate Birth rate Death rate = Growth rate How do we determine population sizes in the real world? Sample of larger population, mark and recapture technique
Limiting Factors Any factor that can affect the size of a population 2 Types: density-independent and densitydependent
Factors that affect population growth: Density-independent factors: Limiting factors that influence a population regardless of how many are in the population Ex) natural disaster, floods Density-dependent factors: Limiting factors that will impact the population as it becomes very large and dense Ex) competition for resources, disease
Population Exponential Model of Population Growth: Population growth under ideal conditions Rapid growth over a short period of time
Population Logistic Model of Population Growth Population growth that is slowed by limiting factors as the population size increases Carrying Capacity = maximum amount of organisms that can live off the resources in an area
Biomes
Factors that define a biome Climate (Precipitation and Temperature) Unique Plant and Animal life Video: Intro to Biomes
Tundra Cold and largely treeless, lichen/moss and grasses/wildflowers Has layer of permafrost (permanently frozen soil) Little precipitation and nutrient poor soil Furthest northern-most biome Reindeer and caribou / polar bears and penguins
Tundra Temperature: -25 to 5 C Precipitation: 0 to 20 cm Soil: Permafrost Vegetation: Mosses, lichen, and short grasses Location: Northern N. America, Europe, and Asia
Taiga Cone-bearing trees; biome south of the tundra Plants adapted to long cold winters, short summers, and nutrient poor soil Animals either hibernate in winter or migrate, wolves and rabbits
Taiga Temperature: -20 to 20 C Precipitation: 5 to 25 cm Soil: Nutrient poor Vegetation: Conifers Location: Northwestern US, Canada; just under Tundra
Deciduous Forest Biome we live in Trees lose leaves in the fall Have pronounced seasons Deer, birds, small animals, and bears
Deciduous Forest Temperature: 10 to 20 C Precipitation: 15 to 30 cm Soil: fertile Vegetation: Broad leaf trees Location: Eastern US, Europe, Japan
Grassland Includes the Steppe, Prairie, and Savanna Dominated by grasses; mid-west USA Too dry to support trees and has rich, fertile soil Prairie dogs and snakes
Grassland Temperature: 5 to 30 C Precipitation: 20 to 35 cm Soil: fertile Vegetation: grasses, herbs, shrubs Location: Central US
Savanna Have alternating wet and dry seasons Plants and animals deal with long periods without rain, some umbrella trees Soil low in nutrients compared to mid-west grasslands Zebra and lion
Savanna Temperature: 25 to 30 C Precipitation: 30 to 35 cm Soil: compact Vegetation: grasses and trees Location: Africa, N. Australia
Desert Very little precipitation Vegetation is sparse except for plants that have adapted to dry conditions Not all are hot Jackrabbits and lizards; cactus and other sebaceous plants
Desert Temperature: 10 to 35 C Precipitation: 15 to 25 cm Soil: sandy Vegetation: cacti, bushes Location: US, Africa, Mexico
Tropical Rainforest Lots of rainfall; tall trees Located on the equator Stable, year round growing season Largest biodiversity on land
Tropical Rainforest Temperature: 25 to 30 C Precipitation: 30 to 40 cm Soil: nutrient poor Vegetation: large trees, large diverse Location: S. and C. America, Africa
Aquatic Biomes
Marine Contains salt water Many zones divide the ocean and different organisms are found in each zone Ex: Oceanic zone (open ocean) whales Intertidal zone (beach) ghost crab Photic zone (has light) algae and seaweed
Zones of the Ocean
Oceanic Zone Characteristics: Open sea Type of Water: Marine Plants and Animals: Whales, dolphins, algae, seaweed
Neritic Zone Characteristics: Over continental shelf, can contain coral reefs, which are the most biodiverse water biome Type of Water: Marine Plants and Animals: Sharks, sponges, shrimp, tuna, kelp
Intertidal Zone Characteristics: Area is exposed to air part of the day due to tides Type of Water: Marine Plants and Animals: sea stars, sand dollars, sea palms, grasses
Other Zones Photic has light Aphotic no light Pelagic area from surface to deep into the ocean Benthic lowest zone of the ocean along the ocean floor
Freshwater: Lakes and Ponds Characteristics: Inland body of water, can vary in size with less than 1% salt content Type of Water: Fresh Plants and Animals: Fish, frogs, ducks, lilypads, trees
Freshwater: Rivers and Streams Characteristics: Running water, curve or meander, make up watersheds Type of Water: Fresh Plants and Animals: Salmon, dragonflies, algae, trees
Estuaries/Wetlands Characteristics: Mixture of fresh and salt water, located along the coast and behind islands Type of Water: Fresh, Salt, and Mixed Plants and Animals: Oysters, crabs, birds, mangrove trees, marsh grass